Salicylic Acid/Methanol Extraction (SAM)
The SAM extraction dissolves alite, belite, and free lime leaving a residue of interstitial phases aluminate and ferrite as well as minor phases periclase and alkali sulfates. The SAM solution consists of 20 g of salicylic acid in 300 ml of methanol. Stir about 5 g of powdered clinker or cement in a stoppered flask containing 300 ml of SAM solution for about 2 hours. Allow the suspension to settle for about 15 minutes then vacuum filter using a 0.45 µm filter and Buchner funnel. Wash the residue with methanol, dry at 90 ºC, and store in a vacuum desiccator. Measuring the mass loss allows the QXRD values to be re-calculated on a whole-sample basis and provides an additional estimate for total silicate content.
Potassium Hydroxide/Sugar Extraction (KOH/Sugar)
The KOH/sugar extraction dissolves the interstitial phases of aluminate and ferrite leaving a residue of silicates and minor phases. First, prepare an extraction solution with 7.5 g of KOH and 7.5 g of sucrose in 75 ml of distilled water. Stir 2.25 g of powdered clinker or cement (heat-treated cement) into a 95 ºC KOH/sugar solution for one minute. Filter the solution using a 0.45 µm filter and Buchner funnel, wash residue with 12 ml of water followed by 25 ml of methanol, dry residue at 90 ºC, and store in a vacuum dessicator. The mass loss is not measured for this extraction as the silicates may also be affected, and that the SAM extraction data are generally sufficient.
Nitric Acid/Methanol Extraction
This extraction dissolves the silicates and aluminates leaving a residue of ferrite and (if present) periclase. The extraction solution is 7% nitric acid in methanol. Ten grams of ground clinker or cement are stirred in to 500 ml of the nitric acid/methanol solution for 30 minutes. The residue is then filtered, rinsed with pure methanol, dried, and stored in a vacuum dessicator. Mass loss is generally not measured for this extraction.